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Written by Ben McInturff
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Thursday, 14 May 2009 04:49 |
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If you've ever been frustrated by the exception message "Failed to enable constraints..." while working with a data table or data table adapter, you understand both the benefits and drawbacks to using the powerful data design tools from Microsoft. When I encounter this error, I usually take a few moments to try to find the non-nullable field in the datatable that for whatever reason is not being returned in the data table. If I am unsuccessful in that, I was passed this awesome way of finding the actual exception by my awesome team lead: - Find the ‘fill’ command that’s erroring (this can usually be found by tracing the stack trace of a debug build).
- If this is a generated method (from the TableAdapters) then there’ll be an attribute at the beginning of the method: [System.Diagnostics.DebuggerNonUserCodeAttribute()]
- Comment out the attribute and set a breakpoint at the Fill command
- Run to the breakpoint and cause the error to happen
- In the watch window add a watch on dataTable.GetErrors()
This method can get right to the problem, and save a ton of checking and previewing the data, and the problems with staged and production data differences. I have also found (also through the wisdom of my team lead) that sometimes if a DataTableAdapter starts behaving weirdly, it can be beneficial to copy all the methods out of the DataTableAdapter, delete it, and then recreate it from scratch. |
